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Effect of cross‐fostering on blood pressure and renal function in the New Zealand genetically hypertensive rat
Author(s) -
Ashton Nick,
Kelly Philip,
Ledingham Janet M
Publication year - 2003
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1046/j.1440-1681.2003.03918.x
Subject(s) - blood pressure , medicine , renal function , endocrinology , basal (medicine) , kidney , renal blood flow , excretion , spontaneously hypertensive rat , insulin
Summary 1. The severity of hypertension displayed by adult spontaneously hypertensive rats (SHR) and Dahl (SS/Jr) rats can be reduced by 20–30 mmHg if the hypertensive pup is cross‐fostered to a normotensive mother within the first 2 weeks of birth. In the SHR, at least, this blood pressure‐lowering effect arises through programming of the neonatal kidney to excrete sodium more effectively. Thus, cross‐fostering may only be effective in lowering pressure in salt‐sensitive hypertensive strains. Accordingly, the aim of the present study was to determine whether cross‐fostering is effective in lowering adult blood pressure in the salt‐resistant New Zealand genetically hypertensive (GH) rat. 2. Genetically hypertensive and control normotensive (N) rat pups were reared by either their natural mothers or a foster mother of the opposite strain (NX and GHX). Blood pressure was tracked from the age of 6–18 weeks, at which time renal function was assessed using standard clearance techniques in anaesthetized rats. Renal function was also assessed in a separate group of young rats at 5–6 weeks of age. 3. Cross‐fostered GHX rats had lower blood pressure than GH rats, but this difference was only apparent until 9 weeks. The NX rats had higher blood pressures than N rats, but again pressure converged at 10 weeks. Basal renal function did not differ between GH and GHX rats or between N and NX rats at either age. However, young GH rats had lower renal blood flow, glomerular filtration rate, urine output and sodium excretion than N rats. 4. These data show that cross‐fostering is effective in lowering blood pressure in GH rats, albeit transiently. The kidneys do not appear to play a role, because renal function did not differ under the current experimental conditions between GH and GHX rats. However, the kidney may play a greater role in the onset of hypertension in the GH rat than previously thought.